Vehicle systems utilize a wide variety of input during operation, some of which is known and some of which is approximated. For example, the tare weight (the unladen weight of a vehicle), the curb weight (the weight of the vehicle with all necessary consumables like motor oil, coolant, a full tank of fuel, etc., but without passengers and cargo) and the gross vehicle weight rating (the maximum allowable total mass of the vehicle) are typically known quantities that can be obtained from the vehicle manufacturer or some other source. Other input, like the actual mass of the vehicle including all of its contents like fuel, passengers, cargo, etc. may not be known with precision, as that quantity changes over time.